1. Field of the Invention
This invention relates to the control by a computer of a milling machine which shapes a blank to form a filter lens for a clip-on accessory to be hitched onto the frame of a pair of eyeglasses whereby the geometry of the filter lens matches the geometry of the half-section of the frame onto which it is clipped.
More particularly, the invention resides in apparatus adapted to orient these eyeglasses with respect to an electronic scanner so that it generates digital data defining the geometry of a half-section of the frame of the eyeglasses, the data being entered into a computer so that it can control the milling machine which impart a matching geometry to the filter lens
2. Status of Prior Art
In our copending application whose entire disclosure is incorporated herein by reference, entitled xe2x80x9cComputer Controlled Milling Machine for Producing Lenses for Clip-On Accessoryxe2x80x9d (SN 136509.7) there is disclosed a milling machine for shaping blanks to create filter lenses for a clip-on accessory having a pair of filter lenses which register with a pair of optical lenses in prescription eyeglasses when the accessory is hitched onto the frame of the eyeglasses. The frame of the eyeglasses is composed of two like half-sections having a predetermined geometry, an optical lens being mounted in each half-section. The filter lenses in the accessory which are joined by a bridge piece have a geometry matching that of the corresponding half-sections of the fame whereby the appearance of the clip-on accessory is fully compatible with that of the eyeglasses.
In this milling machine, the blank to be milled is supported on a rotary worktable and is engaged by a drilling bit that is shifted along X and Y coordinates to cut the blank to form a filter lens having the desired geometry. In the milling machine, the rotary motion of the worktable on which the blank is supported and the movements of the drill bit which act to shape the blank are computer-controlled to impart the desired geometry to the blank.
The blank workpiece on the worktable is engaged by the bit of a drill bit unit mounted on an elevator. The elevator which acts to move the drill bit up and down along a vertical axis, rides on a carriage movable along a horizontal track back and forth to shift the drill bit along a horizontal axis.
The rotary worktable, the elevator and the carriage are driven by respective stepping motors whose incremental advances are controlled by a computer. Digitally stored in the database of the computer is data regarding the geometry of the half-sections of the eyeglass frame on which the accessory is to be hitched. The computer acts to precisely position the drill bit with respect to the blank as it is being rotated, so as to impart thereto the desired geometry.
In order to instruct the computer how to control the milling machine to impart to the filter lens being shaped, a geometry which matches the geometry of the half-section of the eyeglasses frame onto which this lens is to be clipped, the computer must be supplied with digital data that defines this geometry. To this end, the half-sections of the frame of the eyeglasses are scanned by an electronic scanner which generates digital data regarding the frame geometry and supplies this data to the database.
The concern of the present invention is with the physical orientation of the pair of eyeglasses being scanned relative to the scanner so that the digital data generated by the scanner can be processed in the computer to define with a reasonable degree of accuracy the geometry of the frame of the eyeglasses.
In view of the foregoing, the main object of this invention is to provide an apparatus which facilitates scanning by a scanner of a pair of eyeglasses so as to translate the geometry of the frame of these glasses into digital data, the apparatus serving to properly orient the eyeglasses with respect to the scanner.
More particularly, an object of this invention is to provide an apparatus for orienting the glasses with respect to the scanner, which apparatus is constituted by an anchor, a pedestal and a fixture, the anchor being bonded to the window of a scanner unit, the pedestal being attached adhesively to a lens of the eyeglasses and being socketed in the anchor so that a lens of the eyeglasses is seen by the scanner, the fixture facilitating attachment of the pedestal to this lens.
A significant advantage of an apparatus in accordance with the invention is that it is not necessary that the eyeglasses whose geometry is to be copied be precisely oriented with respect to the optical axis of the scanner. Should the orientation be off center, the resultant digital data will not accurately reflect the frame geometry. However, by means of appropriate software associated with the computer into which the digital data from the scanner is entered, the data can be corrected to compensate for this deviation.
Briefly stated, an apparatus in accordance with the invention, when used to orient a pair of eyeglasses with respect to an electronic scanner unit having a window and a scanner optically trained on the window, includes an anchor that is bonded to the window at a site in line with the optical axis of the scanner.
Also provided are a pedestal and a fixture to facilitate adhesively attaching the pedestal to a lens of the eyeglasses. The pedestal, when attached to the lens, is then socketed in the anchor so that the half-section of the frame in which this lens is mounted can then be viewed and scanned by the scanner.
The scanner viewing the anchored eyeglasses generates digital data which defines the geometry of the half-section of the frame of the eyeglasses in which the attached lens is mounted. This data is entered into a computer controlling a milling machine which shapes a blank to form a filter lens for a clip-on accessory whose geometry matches that of the frame half-section.